Responses of wheat (Triticum aestivum) plants grown in a Cd contaminated soil to the application of iron oxide nanoparticles.

The present study demonstrated the possible impacts of iron oxide nanoparticles (Fe NPs) on the alleviation of toxic effects of cadmium (Cd) in wheat and enhance its growth, yield, and Fe biofortification. A pot experiment was conducted in historically Cd-contaminated soil using five levels of Fe NPs (0, 5, 10, 15, and 20 ppm) by soil and foliar application methods. The plants were harvested after 125 days of growth while vegetative parameters, antioxidant capacity, electrolyte leakage (EL) in leaves as well as Cd, and Fe concentrations in wheat grains, roots, and shoots were measured. The results showed that the application of Fe NPs mitigated the Cd toxicity on wheat growth and yield parameters. The exogenous application of Fe NPs enhanced the wheat morphological parameters, photosynthetic pigments, and dry biomass of shoots, roots, spike husks and grains. The activities of super oxide dismutase and peroxidase increased, whereas EL reduced from wheat leaves over control. The Cd concentrations were reduced in wheat tissues and grains whereas Fe concentrations increased with Fe NPs application in a dose-additive manner. The current work suggested that the application of Fe NPs on wheat in Cd-contaminated soils could be employed to improve growth, yield and Fe biofortification as well as reduction in Cd concentrations in plants.

Hussain A ，Ali S ，Rizwan M ，Rehman MZU ，Qayyum MF ，Wang H ，Rinklebe J ... -  《-》

Zinc and iron oxide nanoparticles improved the plant growth and reduced the oxidative stress and cadmium concentration in wheat.

The effects of seed priming with zinc oxide (ZnO) and iron (Fe) nanoparticles (NPs) on the growth and cadmium (Cd) accumulation by wheat (Triticum aestivum) were investigated. Seeds of wheat were primed with different concentrations of either ZnO NPs (0, 25, 50, 75, and 100 mg L-1) or Fe NPs (0, 5, 10, 15, and 20 mg L-1) for 24 h by continuous aeration and then the seeds were sown in a soil which was contaminated with Cd due to long-term application of sewage water. Plants were grown till maturity under natural conditions with 60-70% moisture contents of total soil water holding capacity throughout the experiment. Plant height, spike length, and dry weights of shoots, roots, spikes, and grains were increased with NPs, in particular with the higher rates of NPs. The results depicted that NPs positively affected the photosynthesis of wheat as compared to the control. The NPs reduced the electrolyte leakage and superoxide dismutase and peroxidase activities in leaves of Cd-stressed wheat. The concentrations of Cd in roots, shoots, and grains were significantly decreased with NPs application. The Cd content in the grains was below the threshold level of Cd (0.2 mg kg-1) for cereals when the seeds were treated with higher NPs treatments. The application of ZnO NPs increased the Zn concentrations and Fe NPs increased the Fe concentrations in roots, shoots, and grains. Overall, the NPs play a major role in the increase in biomass, nutrients and decrease in Cd toxicity in wheat.

Rizwan M ，Ali S ，Ali B ，Adrees M ，Arshad M ，Hussain A ，Zia Ur Rehman M ，Waris AA ... -  《-》

Zinc oxide nanoparticles alter the wheat physiological response and reduce the cadmium uptake by plants.

An experiment was performed to explore the interactive impacts of zinc oxide nanoparticles (ZnO NPs) and cadmium (Cd) on growth, yield, antioxidant enzymes, Cd and zinc (Zn) concentrations in wheat (Triticum aestivum). The ZnO NPs were applied both in Cd-contaminated soil and foliar spray (in separate studies) on wheat at different intervals and plants were harvested after physiological maturity. Results depicted that ZnO NPs enhanced the growth, photosynthesis, and grain yield, whereas Cd and Zn concentrations decreased and increased respectively in wheat shoots, roots and grains. The Cd concentrations in the grains were decreased by 30-77%, and 16-78% with foliar and soil application of NPs as compared to the control, respectively. The ZnO NPs reduced the electrolyte leakage while increased SOD and POD activities in leaves of wheat. It can be concluded that ZnO NPs (levels used in the study) could effectively reduce the toxicity and concentration of Cd in wheat whereas increase the Zn concentration in wheat. Thus, ZnO NPs might be helpful in decreasing Cd and increasing Zn biofortification in cereals which might be effective to reduce the hidden hunger in humans owing the deficiency of Zn in cereals.

Hussain A ，Ali S ，Rizwan M ，Zia Ur Rehman M ，Javed MR ，Imran M ，Chatha SAS ，Nazir R ... -  《-》

Combined use of different nanoparticles effectively decreased cadmium (Cd) concentration in grains of wheat grown in a field contaminated with Cd.

Cadmium (Cd) accumulation in arable lands has become a serious matter for food security. Among various approaches, the application of nanoparticles (NPs) for remediation of contaminated water and soils is attaining more popularity worldwide. The current field experiment was executed to explore the impacts of single and combined use of ZnO NPs, Fe NPs and Si NPs on wheat growth and Cd intake by plants in a Cd-contaminated field. Wheat was sown in a field which was contaminated with Cd and was irrigated with the raw-city-effluent while NPs were applied as foliar spray alone and in all possible combinations. The data revealed that straw and grain yields were enhanced in the presence of NPs over control. Chlorophyll, carotenoids contents and antioxidants activities were enhanced while electrolyte leakage was reduced with all NPs over control. In comparison with control, Cd uptake in wheat straw was reduced by 84% and Cd uptake in grain was reduced by 99% in T8 where all three NPs were foliar-applied simultaneously. Zinc (Zn) and iron (Fe) contents were increased in those plants where ZnO and Fe NPs were exogenously applied which revealed that ZnO and Fe NPs enhanced the bio-fortification of Zn and Fe in wheat grains. Overall, foliar application of different NPs is beneficial for better wheat growth, yield, nutrients uptake and to lessen the Cd intake by plants grown in Cd-contaminated soil under real field conditions.

Hussain A ，Rizwan M ，Ali S ，Rehman MZU ，Qayyum MF ，Nawaz R ，Ahmad A ，Asrar M ，Ahmad SR ，Alsahli AA ，Alyemeni MN ... -  《-》

Silicon nanoparticles enhanced the growth and reduced the cadmium accumulation in grains of wheat (Triticum aestivum L.).

The application of silicon (Si) under heavy metal stress is well known, but the use of Si nanoparticles (NPs) under metal stress in not well documented. Thus, the experiments were performed to investigate the impacts of soil and foliar applied Si NPs on wheat (Triticum aestivum L.) growth and cadmium (Cd) accumulation in grains under Cd toxicity. The plants were grown under natural environmental conditions and were harvested after physiological maturity (124 days after sowing). The results demonstrated that Si NPs significantly improved, relative to the control, the dry biomass of shoots, roots, spikes and grains by 24-69%, 14-59%, 34-87%, and 31-96% in foliar spray and by 10-51%, 11-49%, 25-69%, and 27-74% in soil applied Si NPs, respectively. The Si NPs enhanced the leaf gas exchange attributes and chlorophyll a and b concentrations, whereas diminished the oxidative stress in leaves which was indicated by the reduced electrolyte leakage and enhancement in superoxide dismutase and peroxidase activities in leaf under Si NPs treatments over the control. When compared with the control, the foliar spray of Si NPs reduced the Cd contents in shoots, roots, and grains by 16-58%, 19-64%, and 20-82%, respectively, whereas soil applied Si NPs reduced the Cd concentrations in shoots, roots, and grains by 11-53%, 10-59%, and 22-83%, respectively. In comparison with the control, Si concentrations significantly (p ≤ 0.05) increased in the shoots and roots in both foliar and soil supplementation of Si NPs. Our results suggested that Si NPs could improve the yield of wheat and more importantly, reduce the Cd concentrations in the grains. Thus, the use of Si NPs might be a feasible approach in controlling Cd entry into the human body via crops.

Ali S ，Rizwan M ，Hussain A ，Zia Ur Rehman M ，Ali B ，Yousaf B ，Wijaya L ，Alyemeni MN ，Ahmad P ... -  《-》